U.S. patent number 4,448,466 [Application Number 06/320,280] was granted by the patent office on 1984-05-15 for low insertion force connector for printed circuit boards.
This patent grant is currently assigned to NCR Corporation. Invention is credited to Warren W. Porter.
United States Patent |
4,448,466 |
Porter |
* May 15, 1984 |
Low insertion force connector for printed circuit boards
Abstract
An electrical connector provides mechanical advantage in
obtaining high contact force with low insertion force. A pin is
utilized as a cantilever beam to provide high contact force. A
carrier, which is activated by insertion of a printed circuit board
or the like, includes a lever forming part of the electrical
connection. A spring element acts on the carrier to insure the
levers are not in the path of the printed circuit board until after
the printed circuit board makes contact with the carrier. The lever
is displaced by the insertion of the printed circuit board causing
a deflection of the pin. The lever has contact points capable of
causing a piercing action, thereby forming good electrical
contacts.
Inventors: |
Porter; Warren W. (Escondido,
CA) |
Assignee: |
NCR Corporation (Dayton,
OH)
|
[*] Notice: |
The portion of the term of this patent
subsequent to October 26, 1999 has been disclaimed. |
Family
ID: |
23245697 |
Appl.
No.: |
06/320,280 |
Filed: |
November 12, 1981 |
Current U.S.
Class: |
439/59; 439/260;
439/426; 439/630 |
Current CPC
Class: |
H01R
12/87 (20130101) |
Current International
Class: |
H01R
12/16 (20060101); H01R 12/00 (20060101); H01R
023/68 () |
Field of
Search: |
;339/17M,17LM,95R,95D,75MP,176MP |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
2423266 |
|
Dec 1974 |
|
DE |
|
44-22981 |
|
Sep 1969 |
|
JP |
|
53-66348 |
|
Dec 1979 |
|
JP |
|
639056 |
|
Dec 1978 |
|
SU |
|
Primary Examiner: McQuade; John
Attorney, Agent or Firm: Cavender; J. T. Dugas; Edward
Gonzalez; Floyd A.
Claims
I claim:
1. An electrical connector for connecting to an edge contact of a
printed circuit board or the like comprising:
(a) a housing having a longitudinal slot for receiving an edge of a
printed circuit board;
(b) a pin made of an electrically conductive resilient
material;
(c) interconnection means for operatively connecting said pin to
said edge contact, said inteconnection means rotatably positioned
within said housing and actuated by an insertion of the printed
circuit board or the like, said interconnection means being
configured to have two ends such that the first end of said
interconnection means makes a first contact point with said edge
contact when said interconnection means is actuated by the
insertion of said printed circuit board or the like, said
interconnection means rotating as said printed circuit board or the
like is further inserted, and the second end of said
interconnection means makes a second contact point with said pin,
the second end of said interconnection means causing said pin to be
deflected as a result of the rotating motion of said
interconnection means, said deflection causing a force to be
transmitted through said first and second contact points, thereby
permitting a piercing action to occur at said first and second
contact points; and
(d) means for applying a force to said interconnection means to
return said interconnection means to an unrotated position, said
means for applying being effectively inoperative when the printed
circuit board or the like is acting in concert with said electrical
connector.
2. An electrical connector for connecting to an edge contact of a
printed circuit board or the like comprising:
(a) a housing having a longitudinal slot for receiving an edge of a
printed circuit board;
(b) a pin made of an electrically conductive resilient
material;
(c) interconnection means for operatively connecting said pin to
said edge contact, said interconnection means rotatably positioned
within said housing and actuated by an insertion of the printed
circuit board or the like, said interconnection means being
configured to have two ends such that the first end of said
interconnection means makes a first contact point with said edge
contact when said interconnection means is actuated by the
insertion of said printed circuit board or the like, said
interconnection means rotating as said printed circuit board or the
like is further inserted, and the second end of said
interconnection means makes a second contact point with said pin,
the second end of said interconnection means causing said pin to be
deflected as a result of the rotating motion of said
interconnection means, said deflection causing a force to be
transmitted through said first and second contact points, the
rotation reaching a point such that the force contains a component
providing a latching action for the printed circuit board or the
like; and
(d) means for applying a force to said interconnection means to
return said interconnection means to an unrotated position, said
means for applying being effectively inoperative when the printed
circuit board or the like is acting in concert with said electrical
connector.
3. An electrical connector for connecting to an edge of a printed
circuit board or the like comprising:
(a) a housing having a longitudinal slot for receiving an edge of a
printed circuit board;
(b) a pin made of an electrically conductive resilient
material;
(c) interconnection means for operatively connecting said pin to
said edge contact, said interconnection means rotatably positioned
within said housing and actuated by an insertion of the printed
circuit board or the like, said interconnection means being
configured to have two ends such that the first end of said
interconnection means makes a first contact point with said edge
contact when said interconnection means is actuated by the
insertion of said printed circuit board or the like, said
interconnection means rotating as said printed circuit board or the
like is further inserted, and the second end of said
interconnection means makes a second contact point with said pin,
the second end of said interconnection means causing said pin to be
deflected as a result of the rotating motion of said
interconnection means, said deflection causing a force to be
transmitted through said first and second contact points, thereby
permitting a piercing action to occur at said first and second
contact points, and the rotation reaching a point such that the
force contains a component providing a latching action for the
printed circuit board or the like; and
(d) means for applying a force to said interconnection means to
return said interconnection means to an unrotated position, said
means for applying being effectively inoperative when the printed
circuit board or the like is acting in concert with said electrical
connector.
4. An electrical connector comprising:
(a) an electrically insulative housing having two sidewalls, a
front wall, a top wall, a back wall, and a base whose base
centerline is along a surface of the base forming an inside surface
of the electrically insulative housing, the top wall having an
aperture centered in the top wall for receiving a printed circuit
board or the like having a plurality of terminal strips, the
electrically insulative housing further having a cavity formed by
said two sidewalls, said front wall, said back wall, said top wall
and said base;
(b) a plurality of electrically conductive pins arranged in two
rows and being sufficiently flexible for providing a cantilever
action, the two rows being along the base, parallel to and on
oppposite, equidistant sides of the base centerline, each of said
plurality of electrically conductive pins being affixed in and
perpendicular to the base and being spaced equally apart within the
row, and extending through the base a sufficient length to permit
external connections to be made to said plurality of electrically
conductive pins, and further extending into the cavity a sufficient
length to maintain an operative connection to the corresponding
terminal strip of said printed circuit board or the like when said
printed circuit board or the like is fully inserted into said
electrical connector;
(c) a pair of connecting means, each positioned within said cavity
for completing the operative connection between each of said
plurality of electrically conductive pins to a corresponding one of
said terminal strips of said printed circuit board or the like, the
insertion of said printed circuit board or the lke causing said
connecting means to rotate thereby causing the connecting means to
complete said operative connection; and
(d) a pair of rods, each rod corresponding to a respective
connecting means, each rod having a first end firmly affixed at a
point on the base and having a second end extending beyond the
connecting means such that part of a surface of the rod near the
second end is in operative contact with said connecting means, the
point on the base being located such that the rod is slightly
deflected causing the rod to exert a force on the connecting means
in a direction to insure the return of said connecting means to an
unrotated position upon removal of said printed circuit board.
5. An electrical connector system comprising:
(a) a backplate;
(b) at least one printed circuit board or the like, each printed
circuit board or the like having at least one edge contact; and
(c) at least one electrical connector comprising:
(i) a housing having a base, and having an aperture for receiving
said printed circuit board of the like, and further having a cavity
within said housing;
(ii) at least one pin made of an electrically conductive resilient
material extending through the base a sufficient length to permit
external connections to be made to said pins, and further extending
into the cavity a sufficient length to maintain an operative
connection to the corresponding edge contact of said printed
circuit board or the like when said printed circuit board or the
like is fully inserted into the corresponding electrical
connector;
(iii) at least one connecting means, each positioned within said
cavity for completing the operative connection between each of said
electrically conductive pins to a corresponding one of said edge
contacts of said printed circuit board or the like, the insertion
of said printed circuit board or the like causing said connecting
means to rotate thereby causing the connecting means to complete
said operative connection; and
(iv) at least one rod, each rod corresponding to a respective
connecting means, each rod having a first end firmly affixed at a
point on the base and having a second end extending beyond the
connecting means such that a surface along the axis of the rod near
the second end is in operative contact with said connecting means,
the point on the base being such that the rod is slightly deflected
causing the rod to exert a force on the connecting means in a
direction to insure the return of said connecting means to an
unrotated position upon removal of said printed circuit board;
the electrical connectors being affixed to the backplate, the pins
of each connector extending through a corresponding aperture of the
backplate thereby permitting the pins to be interconnected.
Description
BACKGROUND OF THE INVENTION
This invention relates to an electrical connector and more
particularly to a low insertion force connector having a contact
arrangement which provides a good electrical contact for printed
circuit boards having beveled edges.
In many systems and for a variety of reasons, many electronic
elements, components, circuitry, and interconnections are presently
mounted, deposited, printed, or otherwise formed on one or both
sides of a board (a printed circuit board, PCB) or other suitable
substrate. Electrical interconnections of the PCB or the like and a
backpanel or the like of the system are generally accomplished by a
connector.
These connectors generally include a housing which is bolted or
otherwise affixed to the backpanel, and the housing is formed with
a longitudinal slot for receiving one edge of the printed circuit
board or the like. The connector is provided with a plurality of
individual interconnection elements each of which is adapted to
suitably contact the backpanel on one end, and to suitably contact
the printed circuit board or the like on the other end. The
electrical connections provided by these interconnection elements
are formed in various well known manners with the connections to
the backpanel being relatively permanent in comparison to the
connections made with the printed circuit board or the like.
In many connector configurations, the interconnection elements are
formed so that one end of each interconnection element protrudes
through the backpanel and wire-wrapped or otherwise connected.
Connections between the interconnection element and the PCB or the
like are generally made by mechanically biasing the interconnection
elements of the connector into engagement with the edge contacts of
the printed circuit board or the like. This mechanical biasing
force serves two purposes, the first being to provide the
electrical connections and the second being to grip the printed
circuit board or the like, and thus hold the PCB or the like in the
connector. It should be apparent that the biasing force exerted by
the interconnecting elements must be relatively high to insure that
good conductive contacts are made and maintained. The high biasing
force causes a high insertion force of the PCB or the like which
becomes excessive when the number of the interconnection elements
of the connector is of a large quantity, the problem of the high
insertion force being the impetus behind the development of zero
insertion force and low insertion force connectors.
Another problem with these connectors is that the contact areas of
the edge contacts and the interconnecting elements will rub against
each other with considerable force during insertion and removal of
the printed circuit board or the like. Since the edge contacts of a
typical printed circuit board are only a few thousandths of an inch
thick, this rubbing action which occurs during insertion and
removal of the printed circuit board tends to wear away the edge
contacts and may well ruin a PCB after several insertions and
removals. This rubbing action may also wear away high-cost precious
metal on the surface of the interconnecting elements which invites
poor electrical contacts or corrosion and can result in hard to
detect failures of the equipment.
In view of these above stated problems several attempts have been
made to produce what has become known in the art as zero or low
insertion force connector. Generally, these zero or low insertion
force connectors are provided with mechanical actuating mechanisms
which move the contact area of the interconnections elements out of
the insertion and removal path of the printed circuit board or the
like and allow the interconnecting elements to move into engagement
with the edge contacts after the printed circuit board or the like
has been inserted. Such a zero or low insertion force connector is
disclosed in U.S. Pat. No. 4,355,856, issued Oct. 26, 1982,
entitled "Low Insertion Force Connector Using Non-Noble Metal
Contact Plating," by Warren W. Porter, and assigned to the same
assignee as the present application. The referenced Patent
discloses an actuating mechanism which is activated by the
insertion of a printed circuit board or the like causing
interconnecting elements to move and make contact with edge
contacts of the printed circuit board, resulting in a low insertion
force connector and eliminating any rubbing or wiping action
between the edge contacts of the printed circuit board and the
interconnecting elements, the interconnecting elements having sharp
edges for piercing the oxide layer of the edge contact thus forming
good electrical contacts. However, when this connector is utilized
in conjunction with a printed circuit board having beveled edges, a
high probability exists that the connector will not operate
correctly, i.e., the interconnection elements will not properly
engage or make contact with the edge contacts of the printed
circuit board because the edge contacts do not extend to the end of
the printed circuit board but only to the start of the beveled
edge.
Therefore, a need exists for a new and improved zero or low
insertion force connector which allows the use of a printed circuit
board having beveled edges, in addition to a printed circuit board
having non-beveled edges, and simultaneously offers the advantages
of the connector of the aforementioned U.S. Pat. No. 4,355,856.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new low insertion force
connector which may be used with printed circuit boards having
beveled edges has been devised. The electrical connector for
connecting to an edge contact of a printed circuit board or the
like comprises a pin made of an electrically conductive resilient
material, and an interconnection element positioned within the
electrical connector for completing the operative connection
between the pin to the edge contact of the printed circuit board or
the like. The insertion of the printed circuit board or the like
causes the interconnection element to rotate thereby causing the
interconnection element to complete the operative connection. An
element is included which applies a force to the interconnection
element to achieve a ready state.
The electrical connector, for connecting to an edge contact of a
printed circuit board or the like, includes a pin made of an
electrically conductive resilient material and a carrier, made of
an electrically insulative material which is actuated by insertion
of the printed circuit board or the like. A lever, made of an
electrically conductive material and being partially encased within
the carrier, has two ends which are pointed or edged. The carrier
is positioned within the electrical connector such that the first
end of the lever makes a first contact point with the edge contact
when the carrier is actuated by an insertion of the printed circuit
board or the like. The carrier continues a rotation motion as the
printed circuit board or the like is further inserted, and the
second end of the lever makes a second contact point with the pin.
The second end of the lever causes the pin to be deflected as a
result of the rotation motion of the carrier. The deflection causes
a force to be transmitted through the first and second contact
points, thereby to permit a piercing action to occur at the first
and second contact points. A rod is in contact with the carrier and
is configured to exert a force on the carrier in a direction to
insure a ready state.
A specific embodiment of the electrical connector includes an
electrically insulative housing which has two sidewalls, a front
wall, a back wall, a top wall, and a base whose base centerline is
along a surface of the base and parallel to the front and back
walls, the surface of the base forming an inside surface of the
electrically insulative housing. The top wall has an aperture
centered in the top wall for receiving a printed circuit board or
the like having a plurality of terminal strips. The electrically
insulative housing has a cavity formed by the two sidewalls, the
front wall, the back wall, the top wall and the base. A plurality
of electrically conductive pins are arranged in two rows and are
sufficiently flexible for providing a cantilever action. The two
rows are along the base, parallel to and on opposite, equidistant
sides of the base centerline. Each of the plurality of electrically
conductive pins are affixed in and perpendicular to the base,
spaced equally apart within the row, and extend through the base a
sufficient length to permit external connections to be made to the
plurality of electrically conductive pins. The pins further extend
into the cavity a sufficient length to maintain an operative
connection to the corresponding terminal strip of the printed
circuit board or the like when the printed circuit board or the
like is fully inserted into the electrical connector. Connecting
carriers, are each positioned within the cavity for completing the
operative connection between each of the plurality of electrically
conductive pins to a corresponding one of the terminal strips of
the printed circuit board or the like. The insertion of the printed
circuit board or the like causes the connecting carriers to rotate
thereby causing the connecting carriers to complete the operative
connection. A pair of rods, each rod corresponding to a respective
connecting carrier and each rod having a first end which is firmly
affixed at a point on the base and having a second end which
extends beyond the connecting carrier such that a surface of the
rod near the second end is in operative contact with the connecting
carrier. The point on the base is located such that the rod is
slightly deflected causing the rod to exert a force on the
connecting carrier in a direction to insure the ready state of the
electrical connector.
From the foregoing it can be seen that it is a primary object of
the present invention to provide an electrical connector having a
low insertion force.
It is another object of the present invention to provide a low
insertion force electrical connector for use with printed circuit
boards, including printed circuit boards having beveled edges.
It is still another object of the present invention to provide a
low insertion force electrical connector for use with printed
circuit boards having beveled edges while providing good electrical
contacts.
These and other objects of the present invention will become more
apparent when taken in conjunction with the following description,
and attached drawings, wherein like characters indicate like parts
and which drawings form a part of the present application.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end-view cross-section of the patented connector of
the aforementioned U.S. Pat. No. 4,355,856 with the printed circuit
board or the like partially inserted therein;
FIG. 2 is an end-view cross-section of the patented connector with
the printed circuit board withdrawn and the connector in the
initial or ready state and ready to receive the PCB;
FIG. 3 is an end-view cross-section of the patented connector
showing an initial insertion position of a PCB having beveled
edges;
FIG. 4 is a partial end-view cross-section of the patented
connector depicting a stable ready state condition;
FIG. 5 is a partial end-view cross-section of the patented
connector, having modified carriers for use with printed circuit
boards with beveled edges, depicting a condition resulting in an
unstable ready state;
FIG. 6 is a cut-out partial section view of the total connector
assembly;
FIG. 7 is an end-view cross-section of the connector assembly of
FIG. 6 taken along the section line 7--7 without the printed
circuit board inserted;
FIG. 7A is a magnified view of the encircled contact point of FIG.
7;
FIG. 8 is the end-view cross-section of the FIG. 7 connector with
the printed circuit board partially inserted;
FIG. 9 is the end-view cross-section of the FIG. 7 connector with
the printed circuit board inserted further than shown in FIG.
8;
FIG. 10 is the end-view cross-section of the FIG. 7 connector with
the printed circuit board inserted further than shown in FIG.
9;
FIG. 11 is the end-view cross-section of the FIG. 7 connector with
the printed circuit board fully inserted; and
FIGS. 12A and 12B are a cross-sectional view of a partial connector
taken along section line 12A--12A of FIG. 10.
DETAILED DESCRIPTION
In order to understand the operation, advantages, and features of
the connector of the present invention, it would be advantageous to
first describe the construction and operation of the prior art
connector.
The construction of the connector 900 is shown in FIG. 1, the
connector 900 being the same connector as that described in the
aforementioned U.S. Pat. No. 4,355,856, issued Oct. 26, 1982,
entitled, "Low Insertion Force Connector Using Non-Noble Metal
Contact Plating," by Warren W. Porter also the inventor herein, and
assigned to the same assignee as the present invention. FIG. 1 is
an end-view cross-section of the patented connector 900 with the
printed circuit board 160 or the like partially inserted therein.
Referring to FIG. 1, the connector housing, comprising a top wall
100, a front wall 110, a back wall 120, two side walls (not shown,
each side wall having a groove for guiding the insertion of a
printed circuit board), and a base 140, is shown which is made of
an electrically insulative material. The walls and base of the
connector housing form a hollow or cavity 170 within the connector
900. Top wall 100 has an opening 150 for permitting the insertion
of a printed circuit board (PCB) 160 or the like into the connector
900, the PCB 160 having edge contacts or terminal strips 260.
Two rows of pins 180 are permanently fixed in the base 140 which
extends a length outside the connector housing 190 through the base
140 and into the cavity 170. The two rows are on opposite sides of
a base centerline 200 and equidistant therefrom, the base
centerline 200 being along the base surface and parallel to the
front wall 110 and the back wall 120. The pins 180 are spaced apart
equally within the row.
There is an electrically conductive lever 210 for each pin 180
providing the interconnection between the edge contact 260 and the
pin 180, each lever 210 being partially encased in a lever carrier
220, or simply referred to herein as a carrier 220, made of an
electrically insulative material, with both ends of the lever 210
extending outside the carrier 220 and both ends having a sharp
point or edge. Each pin 180 extends far enough into the cavity 170
such that the corresponding lever 210 always maintains pin contact.
Two carriers 220 are positioned within cavity 170, such that the
levers can rotate in a plane substantially perpendicular to the
base centerline 200. The pin 180 is capable of being deflected as a
cantilever beam when a force is applied.
The operation of the patented connector 900 will now be described
in conjunction with an insertion of the PCB 160. Referring to FIG.
2, the PCB 160 is inserted into opening 150 and travels beyond the
edges of levers 210 to the position depicted by PCB 160' where
initial contact is made with carriers 220, the carriers 220 being
shaped such that a portion extends in the path of travel of PCB
160. Referring back to FIG. 1, the PCB 160 continues to travel,
causing rotation of the carriers 220 such that the edges of the
levers 210, which were shown initially resting upon the inner
surface of top wall 100, begin to make contact at contact points
450 with their corresponding edge contacts 260 (or terminal strips)
of PCB 160. Such rotation also causes a force against pins 180 by
levers 210, thereby deflecting the pins 180 from an initial or
ready state. As PCB 160 is further inserted into connector 900, the
leading edge of PCB 160 continues to push against carriers 220, and
together with the contact point 450 made between levers 210 and
edge contacts 260, the carriers 220 are rotated further, the
initial contact points 450 being maintained throughout insertion of
PCB 160 by the knife-like action of the sharp edges of levers 210,
until the PCB 160 is fully inserted.
Of special significance is the ready state. Referring to FIG. 2 the
patented connector 900 is shown in the ready state. In the ready
state, i.e. a condition in which the connector is ready for the PCB
160 insertion, the two carriers 220 are held in position by the
force exerted by the pins 180. The pins 180 in the ready state are
slightly deflected causing the two carrier surfaces 240 to press
against one another, thereby holding carriers 220 in equilibrium
between the pins 180. The sharp edges of the levers 210 hold the
levers 210 at a fixed point on the pins 180. The other end of the
lever 210 is just outside opening 150 (i.e., does not extend into
the opening 150), and is in contact with the inside surface 280 of
top wall 100. In this configuration, the levers 210 are not in the
path of PCB travel. If the ready state is not achieved, i.e. the
levers 210 remain within the path of PCB travel, such condition can
result in improper connector 900 operation and also can result in
jamming the levers of the connector 900 during the next PCB 160
insertion.
Referring to FIG. 3, it can be seen that the connector 900 may
operate improperly for PCBs 160 having beveled edges. For the
geometry of the connector 900 and the carriers 220 as shown, it can
be seen that as the PCB 160 is inserted, and levers 210 start to
rotate as the PCB 160 is pushed against lever carriers 220, the
levers 210 will engage the beveled surface of the PCB 160 and will
not contact the edge connectors 260 because the edge connections do
not extend to the end of the board 160. Therefore, in order to
insure proper contact is made against the edge connectors 260, the
carriers 220 are shaped such that the portion of the carrier 220
which extends into the path of travel is located deeper into the
connector, i.e. surface 310 is further away from opening 150 and
closer to the base 140. The end of the PCB 160 engaging surface
310, which is now lower in the connector, will place edge
connectors 260 in alignment with the points of levers 210 insuring
contact when carriers 220 are rotated.
However, because of the modified shape of carrier 220, the ready
state may be more difficult to achieve, as will be described in
conjunction with FIGS. 4 and 5. FIG. 4 shows a portion of the
end-view cross-section of the patented connector 900. As mentioned
above, it is important that the connector 900 achieve the ready
state when the PCB 160 is extracted. As PCB 160 is extracted, the
carriers 220 rotate as a result of maintaining the fixed contact
point 450 with PCB 160. At the point of extraction of PCB 160 as
shown in FIG. 4, the contact point 450 with PCB 160 is about to be
broken. At this point, the rotation of carriers 220 to the ready
state is a result of the force F being applied by the deflected
pins 180. Since point A, the approximate center of gravity or
centroid of the carriers 220, which may be determined empirically,
is above the line of force F, a moment M is produced causing a
rotation of the carriers to the ready state.
Referring to FIG. 5, there is shown a partial end-view
cross-section of a patented connector 900 having modified carriers
220, shaped to permit the PCB 160 to be inserted further into the
connector before the modified carriers 220 rotate. Once again, at
the point of extraction of PCB 160 as shown in FIG. 5, contact
point 450 is about to be broken. The rotation of carriers 220 up to
this point has been a result of the extraction process, with the
contact points 450 being fixed with the PCB 160. At this point, the
rotation of carriers 220 will be as a result of force F being
applied by the deflected pins 180. However, since point A, the
approximate center of gravity or centroid of the carriers 220,
which may be determined empirically, is on the line of the applied
force F, no rotational motion will be produced. Translational
motion may be produced until the carriers are in contact with each
other at point 460. If the carriers are modified still further to
permit a deeper insertion of PCB 160, the centroid of the modified
carriers 220 may be at a point A' below the force line and produce
a counter-rotational moment M' shown by the dotted circular line
away from the ready state.
As a result, in order to insure that the ready state is attained,
the patented connector is modified to include a spring element. The
connector of the present invention will now be described. The
construction of the preferred embodiment connector 1 of the present
invention is shown in FIGS. 6 and 7. FIG. 6 is a partial cut-out
section view of the total connector assembly and FIG. 7 is an
end-view cross-section of the connector 1 without the printed
circuit board 16 or the like inserted. Referring to FIGS. 6 and 7,
the connector housing, comprising a top wall 10, a front wall 11, a
back wall 12, two side walls 13 (one is shown in FIG. 6) having a
groove 33 for guiding the insertion of a printed circuit board, and
a base 14, is shown which is made of an electrically insulative
material. The walls and base of the connector housing form a hollow
or cavity 17 within the connector 6. Top wall 10 has an opening 15
for permitting the insertion of a printed circuit board (PCB) 16 or
the like into the connector 1, the PCB 16 having edge contacts or
terminal strips 26.
In the preferred embodiment, two rows of pins 18 are permanently
fixed in the base 14 which extends a length outside the connector
housing 19 through the base 14 and into the cavity 17. The two rows
are on opposite sides of a base centerline 20 and equidistant
therefrom, the base centerline 20 being on the base surface and
parallel to the front wall 11 and the back wall 12. The pins 18 are
spaced apart equally within the row. It will be recognized by those
skilled in the art that many alternative configurations may be
devised within the true scope of the invention, including, a single
pin, a single row of pins, or a row or rows of pins not spaced
apart equally.
There is an electrically conductive lever 21 for each pin 18
providing the interconnection between the edge contact 26 and the
pin 18, each lever 21 being partially encased in a lever carrier
22, or simply referred to herein as a carrier 22, made of an
electrically insulative material, with both ends of the lever 21
extending outside the carrier 22 and both ends having a sharp point
or edge. Each pin 18 extends far enough into the cavity 17 such
that the corresponding lever 21 always maintains pin contact. Two
carriers 22 are positioned within cavity 17, such that the levers
can rotate in a plane substantially perpendicular to the base
centerline 20. The pin 18 is capable of being deflected as a
cantilever beam when a force is applied, the cantilever beam action
to be described hereinunder. In addition, spring elements in the
form of a rod 41, which is resilient, are placed within the cavity
17. The rod 41 is affixed to base 14 at one end, and the other end
is allowed to extend beyond a slot 42 in carrier 22 such that a
surface near this end is in contact with the carrier 22. The rod is
slightly deflected to exert a force against the carrier such that,
without the PCB 16 inserted into the connector 1, a moment is
produced to insure the ready state of the connector as described
above, the force being large enough to insure the ready state and
small enough that it does not substantially contribute to the
insertion force. At least one rod is utilized for each carrier.
Thus, in the ready state, i.e. a condition in which the connector
is ready for the PCB 16 insertion, the two carriers 22 are held in
position by the moment produced between the force exerted by the
pins 18 and the force exerted by the rods 41 as described above.
The pins 18 in the ready state are slightly deflected, the moment
produced by the action of the pins 18 and rods 41 causing the two
carrier surfaces 24 to press against one another, thereby holding
carriers 22 in equilibrium between the pins 18. It will be
recognized by those skilled in the art that many alternatives exist
for implementing the spring element for holding the carrier 22 in
the ready position, including a plastic spring molded as part of
the connector body ends.
The sharp edges of the levers 21 hold the levers 21 at a fixed
point on the pins 18. As shown in FIG. 7A, a notch 25 can be placed
in pin 18 to insure the lever 21/pin 18 position is maintained, the
notch 25 being configured so as not to interfere with lever 21
rotation. The other end of the lever 21 is just outside opening 15
and is in contact with the inside surface of top wall 10. The
carrier 22 is so shaped that is doesn't interfere with the lever
21/pin 18 contact during any lever 21 rotation, the rotation of the
lever 21 will be described in detail hereinunder. The carrier 22 is
further shaped such that a portion of the carrier 22 extends in the
path taken by the PCB 16 during insertion. This portion of the
carrier 22 is placed at a distance away from opening 15 such that
the PCB 16 must be inserted deep enough into the connector 1 before
contacting carriers 22 to insure proper contact will be made
between levers 21 and edge contacts 26. The levers 21, pins 18, and
edge contacts 26 may be made of an electrically conductive noble or
non-noble metal. Again it will be recognized by those skilled in
the art that, although the preferred embodiment shows the ends of
the lever 21 having a chisel-like end configuration, the ends of
the lever 21 may be configured to many different shapes while
providing a good contact point with the pin 18 and the edge contact
26 respectively, the shapes including pointed, square edged,
conical, and the like.
FIG. 7 shows the connector 1 in the ready state. The levers 21 are
in the position as mentioned above such that the PCB 16 can travel
beyond the edges of levers 21 to the point depicted by PCB 16'
where initial contact is made with carriers 22, the carriers 22
being shaped such that a portion extends in the path of travel of
PCB 16 as mentioned above.
FIG. 8 shows the connector 1 in which the PCB 16 has traveled a
sufficient distance to cause rotation of the carriers 22 such that
the edges of the levers 21, which were shown initially resting upon
the inner surface of top wall 10, are presently making contact at
contact points 45 with their corresponding edge contacts 26 (or
terminal strips) of PCB 16. Such rotation also causes a force
against pins 18 by lever 21, thereby deflecting the pins 18 from
the initial or ready state. As PCB 16 is further inserted into
connector 1, the leading edge of PCB 16 continues to push against
carriers 22, and together with the contact point 45 made between
levers 21 and edge contacts 26, the carriers 22 are rotated
further, the initial contact points 45 being maintained throughout
insertion of PCB 16 by the knifelike action of the sharp edges of
levers 21.
FIGS. 9 and 10 show interim positions of PCB travel during
insertion and FIG. 11 shows the PCB 16 fully inserted, the PCB 16
travel being stopped by a block 27. It will be recognized by those
skilled in the art that alternative means may be included for
stopping the PCB 16 travel, including a step 34 in groove 33
(reference FIG. 6). FIG. 10 shows the levers 21 having rotated
perpendicular to the PCB 16 causing the maximum deflection of pins
18. From a lever position beyond the perpendicular, there exists a
small component of force along the PCB 16 travel path which results
in a latching action of the PCB 16. The force required for
insertion is that force required to overcome the small force
component along the PCB travel path. It can be seen that the sharp
points or edges at each end of the levers along with a high contact
force caused by pin 18 deflection permits an action which pierces
the oxide layer of the edge contact 26 thus allowing good
electrical connections. It will be understood by those skilled in
the art that the piercing action of the oxide layer of edge contact
26 includes actions such as friction, rubbing, knifing, cutting,
etc., achieved by the lever 21 ends having alternative
configurations mentioned above.
FIGS. 12A and 12B are a cross-sectional view of a partial connector
1 taken along section line 12A--12A of FIG. 10. FIG. 12A shows
levers 21A through 21D mounted in carrier 22 and by some error,
shows lever 21A extending farther out of carrier 22 than levers
21B, 21C, and 21D on the side making contact with PCB 16. In such
case, lever 21A has created a high-spot thereby preventing levers
21B, 21C, and 21D from making any contact with their corresponding
edge contacts 26. Pins 18A through 18D press against their
respective levers 21A through 21D, pin 18A being the only pin
benefitting from the cantilever action. In an alternative
embodiment, in order to correct for the error or to compensate for
manufacturing tolerances, the levers 21 can be loosely fitted into
the carrier 22, permitting the lever 21 to travel along its length,
as indicated by the arrows of FIG. 12B, within the carrier 22. In
this manner the lever 21 is responsive to the cantilever action of
its respective pin 18 nullifying the effect of the high-spot.
While there has been shown what is considered to be the preferred
embodiment of the invention, it will be manifest that many changes
and modifications can be made therein without departing from the
essential spirit and scope of the invention. It is intended,
therefore, in the annexed claims, to cover all such changes and
modifications which fall within the true scope of the
invention.
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